"This piston is amazing, but, highly recommend that you be an experienced tech for this piston. The reason i say that is because this is a 14 tooth piston, which requires you to remove the last tooth off your sector gear, if you dont, you will have the piston come forward before the gears are out of the way, shredding it and making it sound god awful. This is important that you do this! Now, this is considered short stroking, so, you will loose FPS with this piston since it isnt being pulled back nearly as far. BUT this will give you a faster cycle time and trigger response, but only by a small margin. I use this piston in my custom gun, V.2 gearbox with a Madbull M110, Modify Torus Gearbox shell 8mm, 8mm bearings, Angel custom cylinder (red silent piston kit), SHS piston head, G&P cylinder head, this piston, standard ratio CNC steel gears by BRAVO, and a Lonex A3 motor. Shimmed correctly i am getting 24.5 RPS on a 11.1 lipo which is perfect for me because i am on a profesional team and my gun must be milsim legal (25rps down) and my gun shoots 330FPS with a +/- 2 fps with .28g BB's, which roughly equals about 390~ FPS. Overall, i really like this piston, and its extremely strong. I have used a lot of different pistons, Raptor Airsoft, Madbull, AIM, and out of all of them, i feel like the teeth on this piston are stronger, or just better made. Now, dont let the fact that its an aluminium body fool you, because it is still very light. It is heavier than a Madbull piston, but, only by a little. Which, for a set up either below 30rps or over an m130 spring, this piston is perfect.